The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Lithotripsy is a common method for fragmenting stones, or calculi, in the urinary tract, kidneys, and/or bladder. Most lithotripsy devices use ultrasound, laser, or pneumatic energy sources to fragment such stones into smaller pieces for easier removal from the patient's urologic system. Typically, the lithotripter includes a shaft connected to an electrically controlled driver or a pneumatic actuator. The shaft is inserted into the patient's anatomy to a location near the stone, and energy of a determined pattern is sent through the shaft to impact the stone with the shaft to create a jackhammer or drilling effect on the stone. The tip of the shaft typically has a flat surface. The stone fragments are then removed by irrigation and/or baskets, typically through the center of the shaft by suction.
Among the literature that can pertain to this technology include the following patent documents and published patent applications: US 2010/0204617; U.S. Pat. No. 4,708,127; U.S. Pat. No. 5,042,460; U.S. Pat. No. 5,192,889; U.S. Pat. No. 5,358,466; U.S. Pat. No. 6,689,087; U.S. Pat. No. 8,038,693; U.S. Pat. No. 6,402,046; U.S. Pat. No. 7,942,809; US 2003/0222535; and U.S. Pat. No. 8,038,630, all incorporated by reference for all purposes.
The tip of the lithotripter shaft typically has a smooth, flat surface. Usage of tips with smooth faces on bladder, kidney, or ureter tissue has been found in studies to be safe against tissue damage or perforation. While providing more protection, however, the smooth, flat tip easily slips off of the stone, which may prolong the stone-breaking procedure as the physician repeatedly tries to contact the stone with the tip. Furthermore, if the physician applies excess pressure to the stone via the tip, the vibration of the shaft is dampened and less effective. Accordingly, there exists a need for an improved apparatus and procedure for fragmenting stones.